diff --git a/copyparty/__main__.py b/copyparty/__main__.py
index 2d1c63ad..b15ec3e7 100644
--- a/copyparty/__main__.py
+++ b/copyparty/__main__.py
@@ -8,14 +8,11 @@ __copyright__ = 2019
 __license__ = "MIT"
 __url__ = "https://github.com/9001/copyparty/"
 
-import time
 import argparse
-import threading
 from textwrap import dedent
-import multiprocessing as mp
 
 from .__version__ import S_VERSION, S_BUILD_DT
-from .tcpsrv import TcpSrv
+from .svchub import SvcHub
 
 
 class RiceFormatter(argparse.HelpFormatter):
@@ -38,13 +35,6 @@ class RiceFormatter(argparse.HelpFormatter):
 
 
 def main():
-    try:
-        # support vscode debugger (bonus: same behavior as on windows)
-        mp.set_start_method("spawn", True)
-    except AttributeError:
-        # py2.7 probably
-        pass
-
     ap = argparse.ArgumentParser(
         formatter_class=RiceFormatter,
         prog="copyparty",
@@ -84,19 +74,7 @@ def main():
     ap.add_argument("-nw", action="store_true", help="benchmark: disable writing")
     al = ap.parse_args()
 
-    tcpsrv = TcpSrv(al)
-    thr = threading.Thread(target=tcpsrv.run)
-    thr.daemon = True
-    thr.start()
-
-    # winxp/py2.7 support: thr.join() kills signals
-    try:
-        while True:
-            time.sleep(9001)
-    except KeyboardInterrupt:
-        print("OPYTHAT")
-        tcpsrv.shutdown()
-        print("nailed it")
+    SvcHub(al).run()
 
 
 if __name__ == "__main__":
diff --git a/copyparty/broker_mp.py b/copyparty/broker_mp.py
new file mode 100644
index 00000000..d8278b10
--- /dev/null
+++ b/copyparty/broker_mp.py
@@ -0,0 +1,128 @@
+#!/usr/bin/env python
+# coding: utf-8
+from __future__ import print_function, unicode_literals
+
+import time
+import threading
+import multiprocessing as mp
+
+from .__init__ import PY2, WINDOWS
+from .broker_mpw import MpWorker
+
+
+if PY2 and not WINDOWS:
+    from multiprocessing.reduction import ForkingPickler
+    from StringIO import StringIO as MemesIO  # pylint: disable=import-error
+
+
+class BrokerMp(object):
+    """external api; manages MpWorkers"""
+
+    def __init__(self, hub):
+        self.hub = hub
+        self.log = hub.log
+        self.args = hub.args
+
+        self.mutex = threading.Lock()
+
+        self.procs = []
+
+        cores = self.args.j
+        if cores is None:
+            cores = mp.cpu_count()
+
+        self.log("broker", "booting {} subprocesses".format(cores))
+        for n in range(cores):
+            q_pend = mp.Queue(1)
+            q_yield = mp.Queue(64)
+
+            proc = mp.Process(target=MpWorker, args=(q_pend, q_yield, self.args, n))
+            proc.q_pend = q_pend
+            proc.q_yield = q_yield
+            proc.nid = n
+            proc.clients = {}
+            proc.workload = 0
+
+            thr = threading.Thread(target=self.collector, args=(proc,))
+            thr.daemon = True
+            thr.start()
+
+            self.procs.append(proc)
+            proc.start()
+
+        if True:
+            thr = threading.Thread(target=self.debug_load_balancer)
+            thr.daemon = True
+            thr.start()
+
+    def shutdown(self):
+        self.log("broker", "shutting down")
+        for proc in self.procs:
+            thr = threading.Thread(target=proc.q_pend.put(["shutdown"]))
+            thr.start()
+
+        with self.mutex:
+            procs = self.procs
+            self.procs = []
+
+        while procs:
+            if procs[-1].is_alive():
+                time.sleep(0.1)
+                continue
+
+            procs.pop()
+
+    def collector(self, proc):
+        while True:
+            msg = proc.q_yield.get()
+            k = msg[0]
+
+            if k == "log":
+                self.log(*msg[1:])
+
+            elif k == "workload":
+                with self.mutex:
+                    proc.workload = msg[1]
+
+            elif k == "httpdrop":
+                addr = msg[1]
+
+                with self.mutex:
+                    del proc.clients[addr]
+                    if not proc.clients:
+                        proc.workload = 0
+
+                self.hub.tcpsrv.num_clients.add(-1)
+
+    def put(self, retq, act, *args):
+        if act == "httpconn":
+            sck, addr = args
+            sck2 = sck
+            if PY2:
+                buf = MemesIO()
+                ForkingPickler(buf).dump(sck)
+                sck2 = buf.getvalue()
+
+            proc = sorted(self.procs, key=lambda x: x.workload)[0]
+            proc.q_pend.put(["httpconn", sck2, addr])
+
+            with self.mutex:
+                proc.clients[addr] = 50
+                proc.workload += 50
+        else:
+            raise Exception("what is " + str(act))
+
+    def debug_load_balancer(self):
+        last = ""
+        while self.procs:
+            msg = ""
+            for proc in self.procs:
+                msg += "\033[1m{}\033[0;36m{:4}\033[0m ".format(
+                    len(proc.clients), proc.workload
+                )
+
+            if msg != last:
+                last = msg
+                print(msg)
+
+            time.sleep(0.1)
diff --git a/copyparty/broker_mpw.py b/copyparty/broker_mpw.py
new file mode 100644
index 00000000..522cf10b
--- /dev/null
+++ b/copyparty/broker_mpw.py
@@ -0,0 +1,94 @@
+#!/usr/bin/env python
+# coding: utf-8
+from __future__ import print_function, unicode_literals
+
+import sys
+import time
+import signal
+import threading
+
+from .__init__ import PY2, WINDOWS
+from .httpsrv import HttpSrv
+
+if PY2 and not WINDOWS:
+    import pickle  # nosec
+
+
+class MpWorker(object):
+    """one single mp instance"""
+
+    def __init__(self, q_pend, q_yield, args, n):
+        self.q_pend = q_pend
+        self.q_yield = q_yield
+        self.args = args
+        self.n = n
+
+        self.mutex = threading.Lock()
+        self.workload_thr_active = False
+
+        # we inherited signal_handler from parent,
+        # replace it with something harmless
+        signal.signal(signal.SIGINT, self.signal_handler)
+
+        self.httpsrv = HttpSrv(self.args, self.log)
+        self.httpsrv.disconnect_func = self.httpdrop
+
+        # on winxp and some other platforms,
+        # use thr.join() to block all signals
+        thr = threading.Thread(target=self.main)
+        thr.daemon = True
+        thr.start()
+        thr.join()
+
+    def signal_handler(self, signal, frame):
+        # print('k')
+        pass
+
+    def log(self, src, msg):
+        self.q_yield.put(["log", src, msg])
+
+    def logw(self, msg):
+        self.log("mp{}".format(self.n), msg)
+
+    def httpdrop(self, addr):
+        self.q_yield.put(["httpdrop", addr])
+
+    def main(self):
+        while True:
+            d = self.q_pend.get()
+
+            # self.logw("work: [{}]".format(d[0]))
+            if d[0] == "shutdown":
+                self.logw("ok bye")
+                sys.exit(0)
+                return
+
+            elif d[0] == "httpconn":
+                sck = d[1]
+                if PY2:
+                    sck = pickle.loads(sck)  # nosec
+
+                self.httpsrv.accept(sck, d[2])
+
+                with self.mutex:
+                    if not self.workload_thr_active:
+                        self.workload_thr_alive = True
+                        thr = threading.Thread(target=self.thr_workload)
+                        thr.daemon = True
+                        thr.start()
+
+            else:
+                raise Exception("what is " + str(d[0]))
+
+    def thr_workload(self):
+        """announce workloads to MpSrv (the mp controller / loadbalancer)"""
+        # avoid locking in extract_filedata by tracking difference here
+        while True:
+            time.sleep(0.2)
+            with self.mutex:
+                if self.httpsrv.num_clients() == 0:
+                    # no clients rn, termiante thread
+                    self.workload_thr_alive = False
+                    return
+
+            self.q_yield.put(["workload", self.httpsrv.workload])
diff --git a/copyparty/broker_thr.py b/copyparty/broker_thr.py
new file mode 100644
index 00000000..250069b9
--- /dev/null
+++ b/copyparty/broker_thr.py
@@ -0,0 +1,36 @@
+#!/usr/bin/env python
+# coding: utf-8
+from __future__ import print_function, unicode_literals
+
+import threading
+
+from .httpsrv import HttpSrv
+
+
+class BrokerThr(object):
+    """external api; behaves like BrokerMP but using plain threads"""
+
+    def __init__(self, hub):
+        self.hub = hub
+        self.log = hub.log
+        self.args = hub.args
+
+        self.mutex = threading.Lock()
+
+        self.httpsrv = HttpSrv(self.args, self.log)
+        self.httpsrv.disconnect_func = self.httpdrop
+
+    def shutdown(self):
+        # self.log("broker", "shutting down")
+        pass
+
+    def put(self, retq, act, *args):
+        if act == "httpconn":
+            sck, addr = args
+            self.httpsrv.accept(sck, addr)
+
+        else:
+            raise Exception("what is " + str(act))
+
+    def httpdrop(self, addr):
+        self.hub.tcpsrv.num_clients.add(-1)
diff --git a/copyparty/mpsrv.py b/copyparty/mpsrv.py
deleted file mode 100644
index 84c04fa5..00000000
--- a/copyparty/mpsrv.py
+++ /dev/null
@@ -1,216 +0,0 @@
-#!/usr/bin/env python
-# coding: utf-8
-from __future__ import print_function, unicode_literals
-
-import sys
-import time
-import signal
-import threading
-import multiprocessing as mp
-
-from .__init__ import PY2, WINDOWS
-from .httpsrv import HttpSrv
-
-if PY2 and not WINDOWS:
-    from multiprocessing.reduction import ForkingPickler
-    from StringIO import StringIO as MemesIO  # pylint: disable=import-error
-    import pickle  # nosec
-
-
-class MpWorker(object):
-    """
-    one single mp instance, wraps one HttpSrv,
-    the HttpSrv api exposed to TcpSrv proxies like
-    MpSrv -> (this) -> HttpSrv
-    """
-
-    def __init__(self, q_pend, q_yield, args, n):
-        self.q_pend = q_pend
-        self.q_yield = q_yield
-        self.args = args
-        self.n = n
-
-        self.mutex = threading.Lock()
-        self.workload_thr_active = False
-
-        # we inherited signal_handler from parent,
-        # replace it with something harmless
-        signal.signal(signal.SIGINT, self.signal_handler)
-
-        # on winxp and some other platforms,
-        # use thr.join() to block all signals
-        thr = threading.Thread(target=self.main)
-        thr.daemon = True
-        thr.start()
-        thr.join()
-
-    def signal_handler(self, signal, frame):
-        # print('k')
-        pass
-
-    def log(self, src, msg):
-        self.q_yield.put(["log", src, msg])
-
-    def logw(self, msg):
-        self.log("mp{}".format(self.n), msg)
-
-    def disconnect_cb(self, addr):
-        self.q_yield.put(["dropclient", addr])
-
-    def main(self):
-        self.httpsrv = HttpSrv(self.args, self.log)
-        self.httpsrv.disconnect_func = self.disconnect_cb
-
-        while True:
-            d = self.q_pend.get()
-
-            # self.logw("work: [{}]".format(d[0]))
-            if d[0] == "shutdown":
-                self.logw("ok bye")
-                sys.exit(0)
-                return
-
-            sck = d[1]
-            if PY2:
-                sck = pickle.loads(sck)  # nosec
-
-            self.httpsrv.accept(sck, d[2])
-
-            with self.mutex:
-                if not self.workload_thr_active:
-                    self.workload_thr_alive = True
-                    thr = threading.Thread(target=self.thr_workload)
-                    thr.daemon = True
-                    thr.start()
-
-    def thr_workload(self):
-        """announce workloads to MpSrv (the mp controller / loadbalancer)"""
-        # avoid locking in extract_filedata by tracking difference here
-        while True:
-            time.sleep(0.2)
-            with self.mutex:
-                if self.httpsrv.num_clients() == 0:
-                    # no clients rn, termiante thread
-                    self.workload_thr_alive = False
-                    return
-
-            self.q_yield.put(["workload", self.httpsrv.workload])
-
-
-class MpSrv(object):
-    """
-    same api as HttpSrv except uses multiprocessing to dodge gil,
-    a collection of MpWorkers are made (one per subprocess)
-    and each MpWorker creates one actual HttpSrv
-    """
-
-    def __init__(self, args, log_func):
-        self.log = log_func
-        self.args = args
-
-        self.disconnect_func = None
-        self.mutex = threading.Lock()
-
-        self.procs = []
-
-        cores = args.j
-        if cores is None:
-            cores = mp.cpu_count()
-
-        self.log("mpsrv", "booting {} subprocesses".format(cores))
-        for n in range(cores):
-            q_pend = mp.Queue(1)
-            q_yield = mp.Queue(64)
-
-            proc = mp.Process(target=MpWorker, args=(q_pend, q_yield, args, n))
-            proc.q_pend = q_pend
-            proc.q_yield = q_yield
-            proc.nid = n
-            proc.clients = {}
-            proc.workload = 0
-
-            thr = threading.Thread(target=self.collector, args=(proc,))
-            thr.daemon = True
-            thr.start()
-
-            self.procs.append(proc)
-            proc.start()
-
-        if True:
-            thr = threading.Thread(target=self.debug_load_balancer)
-            thr.daemon = True
-            thr.start()
-
-    def num_clients(self):
-        with self.mutex:
-            return sum(len(x.clients) for x in self.procs)
-
-    def shutdown(self):
-        self.log("mpsrv", "shutting down")
-        for proc in self.procs:
-            thr = threading.Thread(target=proc.q_pend.put(["shutdown"]))
-            thr.start()
-
-        with self.mutex:
-            procs = self.procs
-            self.procs = []
-
-        while procs:
-            if procs[-1].is_alive():
-                time.sleep(0.1)
-                continue
-
-            procs.pop()
-
-    def collector(self, proc):
-        while True:
-            msg = proc.q_yield.get()
-            k = msg[0]
-
-            if k == "log":
-                self.log(*msg[1:])
-
-            if k == "workload":
-                with self.mutex:
-                    proc.workload = msg[1]
-
-            if k == "dropclient":
-                addr = msg[1]
-
-                with self.mutex:
-                    del proc.clients[addr]
-                    if not proc.clients:
-                        proc.workload = 0
-
-                if self.disconnect_func:
-                    self.disconnect_func(addr)  # pylint: disable=not-callable
-
-    def accept(self, sck, addr):
-        proc = sorted(self.procs, key=lambda x: x.workload)[0]
-
-        sck2 = sck
-        if PY2:
-            buf = MemesIO()
-            ForkingPickler(buf).dump(sck)
-            sck2 = buf.getvalue()
-
-        proc.q_pend.put(["socket", sck2, addr])
-
-        with self.mutex:
-            proc.clients[addr] = 50
-            proc.workload += 50
-
-    def debug_load_balancer(self):
-        last = ""
-        while self.procs:
-            msg = ""
-            for proc in self.procs:
-                msg += "\033[1m{}\033[0;36m{:4}\033[0m ".format(
-                    len(proc.clients), proc.workload
-                )
-
-            if msg != last:
-                last = msg
-                print(msg)
-
-            time.sleep(0.1)
diff --git a/copyparty/msgsvc.py b/copyparty/msgsvc.py
deleted file mode 100644
index d18554f1..00000000
--- a/copyparty/msgsvc.py
+++ /dev/null
@@ -1,15 +0,0 @@
-#!/usr/bin/env python
-# coding: utf-8
-from __future__ import print_function, unicode_literals
-
-
-class MsgSvc(object):
-    def __init__(self, log_func):
-        self.log_func = log_func
-        print("hi")
-
-    def put(self, msg):
-        if msg[0] == "log":
-            return self.log_func(*msg[1:])
-
-        raise Exception("bad msg type: " + str(msg))
diff --git a/copyparty/svchub.py b/copyparty/svchub.py
new file mode 100644
index 00000000..af3c7a30
--- /dev/null
+++ b/copyparty/svchub.py
@@ -0,0 +1,119 @@
+#!/usr/bin/env python
+# coding: utf-8
+from __future__ import print_function, unicode_literals
+
+import sys
+import time
+import threading
+import multiprocessing as mp
+from datetime import datetime, timedelta
+import calendar
+
+from .__init__ import PY2, WINDOWS
+from .tcpsrv import TcpSrv
+
+
+class SvcHub(object):
+    """
+    Hosts all services which cannot be parallelized due to reliance on monolithic resources.
+    Creates a Broker which does most of the heavy stuff; hosted services can use this to perform work:
+        hub.broker.put(retq, action, arg1, argN).
+    
+    Either BrokerThr (plain threads) or BrokerMP (multiprocessing) is used depending on configuration.
+    To receive any output returned by action, provide a queue-object for retq, else None.
+    """
+
+    def __init__(self, args):
+        self.args = args
+
+        self.log_mutex = threading.Lock()
+        self.next_day = 0
+
+        # initiate all services to manage
+        self.tcpsrv = TcpSrv(self)
+
+        # decide which worker impl to use
+        if self.check_mp_enable():
+            from .broker_mp import BrokerMp as Broker
+        else:
+            self.log("root", "cannot efficiently use multiple CPU cores")
+            from .broker_thr import BrokerThr as Broker
+
+        self.broker = Broker(self)
+
+    def run(self):
+        thr = threading.Thread(target=self.tcpsrv.run)
+        thr.daemon = True
+        thr.start()
+
+        # winxp/py2.7 support: thr.join() kills signals
+        try:
+            while True:
+                time.sleep(9001)
+        except KeyboardInterrupt:
+            print("OPYTHAT")
+            self.tcpsrv.shutdown()
+            self.broker.shutdown()
+            print("nailed it")
+
+    def log(self, src, msg):
+        """handles logging from all components"""
+        now = time.time()
+        if now >= self.next_day:
+            dt = datetime.utcfromtimestamp(now)
+            print("\033[36m{}\033[0m".format(dt.strftime("%Y-%m-%d")))
+
+            # unix timestamp of next 00:00:00 (leap-seconds safe)
+            day_now = dt.day
+            while dt.day == day_now:
+                dt += timedelta(hours=12)
+
+            dt = dt.replace(hour=0, minute=0, second=0)
+            self.next_day = calendar.timegm(dt.utctimetuple())
+
+        with self.log_mutex:
+            ts = datetime.utcfromtimestamp(now).strftime("%H:%M:%S")
+            print("\033[36m{} \033[33m{:21} \033[0m{}".format(ts, src, msg))
+
+    def check_mp_support(self):
+        vmin = sys.version_info[1]
+        if WINDOWS:
+            msg = "need python 3.3 or newer for multiprocessing;"
+            if PY2:
+                # py2 pickler doesn't support winsock
+                return msg
+            elif vmin < 3:
+                return msg
+        else:
+            msg = "need python 2.7 or 3.3+ for multiprocessing;"
+            if not PY2 and vmin < 3:
+                return msg
+
+        try:
+            x = mp.Queue(1)
+            x.put(["foo", "bar"])
+            if x.get()[0] != "foo":
+                raise Exception()
+        except:
+            return "multiprocessing is not supported on your platform;"
+
+        return None
+
+    def check_mp_enable(self):
+        if self.args.j == 0:
+            self.log("root", "multiprocessing disabled by argument -j 0;")
+            return False
+
+        try:
+            # support vscode debugger (bonus: same behavior as on windows)
+            mp.set_start_method("spawn", True)
+        except AttributeError:
+            # py2.7 probably, anyways dontcare
+            pass
+
+        err = self.check_mp_support()
+        if not err:
+            return True
+        else:
+            self.log("root", err)
+            return False
diff --git a/copyparty/tcpsrv.py b/copyparty/tcpsrv.py
index a65706ff..0473808d 100644
--- a/copyparty/tcpsrv.py
+++ b/copyparty/tcpsrv.py
@@ -3,30 +3,24 @@
 from __future__ import print_function, unicode_literals
 
 import re
-import sys
 import time
 import socket
-import threading
-import multiprocessing as mp
-from datetime import datetime, timedelta
-import calendar
 
-from .__init__ import PY2, WINDOWS
-from .util import chkcmd
+from .util import chkcmd, Counter
 
 
 class TcpSrv(object):
     """
-    toplevel component starting everything else,
-    tcplistener which forwards clients to httpsrv
-    (through mpsrv if platform provides support)
+    tcplistener which forwards clients to Hub
+    which then uses the least busy HttpSrv to handle it
     """
 
-    def __init__(self, args):
-        self.args = args
+    def __init__(self, hub):
+        self.hub = hub
+        self.args = hub.args
+        self.log = hub.log
 
-        self.log_mutex = threading.Lock()
-        self.next_day = 0
+        self.num_clients = Counter()
 
         ip = "127.0.0.1"
         if self.args.i == ip:
@@ -36,7 +30,7 @@ class TcpSrv(object):
 
         for ip, desc in sorted(eps.items(), key=lambda x: x[1]):
             self.log(
-                "root",
+                "tcpsrv",
                 "available @ http://{}:{}/  (\033[33m{}\033[0m)".format(
                     ip, self.args.p, desc
                 ),
@@ -59,84 +53,19 @@ class TcpSrv(object):
     def run(self):
         self.srv.listen(self.args.nc)
 
-        self.log("root", "listening @ {0}:{1}".format(self.args.i, self.args.p))
+        self.log("tcpsrv", "listening @ {0}:{1}".format(self.args.i, self.args.p))
 
-        self.httpsrv = self.create_server()
         while True:
-            if self.httpsrv.num_clients() >= self.args.nc:
+            if self.num_clients.v >= self.args.nc:
                 time.sleep(0.1)
                 continue
 
             sck, addr = self.srv.accept()
-            self.httpsrv.accept(sck, addr)
+            self.num_clients.add()
+            self.hub.broker.put(None, "httpconn", sck, addr)
 
     def shutdown(self):
-        self.httpsrv.shutdown()
-
-    def check_mp_support(self):
-        vmin = sys.version_info[1]
-        if WINDOWS:
-            msg = "need python 3.3 or newer for multiprocessing;"
-            if PY2:
-                # py2 pickler doesn't support winsock
-                return msg
-            elif vmin < 3:
-                return msg
-        else:
-            msg = "need python 2.7 or 3.3+ for multiprocessing;"
-            if not PY2 and vmin < 3:
-                return msg
-
-        try:
-            x = mp.Queue(1)
-            x.put(["foo", "bar"])
-            if x.get()[0] != "foo":
-                raise Exception()
-        except:
-            return "multiprocessing is not supported on your platform;"
-
-        return ""
-
-    def create_server(self):
-        if self.args.j == 0:
-            self.log("root", "multiprocessing disabled by argument -j 0;")
-            return self.create_threading_server()
-
-        err = self.check_mp_support()
-        if err:
-            self.log("root", err)
-            return self.create_threading_server()
-
-        return self.create_multiprocessing_server()
-
-    def create_threading_server(self):
-        from .httpsrv import HttpSrv
-
-        self.log("root", "cannot efficiently use multiple CPU cores")
-        return HttpSrv(self.args, self.log)
-
-    def create_multiprocessing_server(self):
-        from .mpsrv import MpSrv
-
-        return MpSrv(self.args, self.log)
-
-    def log(self, src, msg):
-        now = time.time()
-        if now >= self.next_day:
-            dt = datetime.utcfromtimestamp(now)
-            print("\033[36m{}\033[0m".format(dt.strftime("%Y-%m-%d")))
-
-            # unix timestamp of next 00:00:00 (leap-seconds safe)
-            day_now = dt.day
-            while dt.day == day_now:
-                dt += timedelta(hours=12)
-
-            dt = dt.replace(hour=0, minute=0, second=0)
-            self.next_day = calendar.timegm(dt.utctimetuple())
-
-        with self.log_mutex:
-            ts = datetime.utcfromtimestamp(now).strftime("%H:%M:%S")
-            print("\033[36m{} \033[33m{:21} \033[0m{}".format(ts, src, msg))
+        self.log("tcpsrv", "ok bye")
 
     def detect_interfaces(self, ext_ip):
         eps = {}
@@ -148,7 +77,7 @@ class TcpSrv(object):
             ip_addr = None
 
         if ip_addr:
-            r = re.compile("^\s+inet ([^ ]+)/.* (.*)")
+            r = re.compile(r"^\s+inet ([^ ]+)/.* (.*)")
             for ln in ip_addr.split("\n"):
                 try:
                     ip, dev = r.match(ln.rstrip()).groups()
diff --git a/copyparty/util.py b/copyparty/util.py
index 0b8f44c5..df7fb9cc 100644
--- a/copyparty/util.py
+++ b/copyparty/util.py
@@ -5,23 +5,38 @@ from __future__ import print_function, unicode_literals
 import re
 import sys
 import hashlib
+import threading
 import subprocess as sp  # nosec
 
 from .__init__ import PY2
+from .stolen import surrogateescape
 
 if not PY2:
     from urllib.parse import unquote_to_bytes as unquote
     from urllib.parse import quote_from_bytes as quote
 else:
     from urllib import unquote  # pylint: disable=no-name-in-module
-    from urllib import quote
+    from urllib import quote  # pylint: disable=no-name-in-module
 
-from .stolen import surrogateescape
 
 surrogateescape.register_surrogateescape()
 FS_ENCODING = sys.getfilesystemencoding()
 
 
+class Counter(object):
+    def __init__(self, v=0):
+        self.v = v
+        self.mutex = threading.Lock()
+
+    def add(self, delta=1):
+        with self.mutex:
+            self.v += delta
+
+    def set(self, absval):
+        with self.mutex:
+            self.v = absval
+
+
 class Unrecv(object):
     """
     undo any number of socket recv ops